/Engine/Source/Runtime/Engine/Public/StereoRenderTargetManager.h
Retrieves HDR information about the stereo device, if any is available. The default implementation always returns false to indicate that the information from the monitor can be used instead.
true, if HDR information is available for the stereo device
virtual bool HDRGetMetaDataForStereo ( EDisplayOutputFormat & OutDisplayOutputFormat, EDisplayColorGamut & OutDisplayColorGamut, bool & OutbHDRSupported )